UCC5630A
Multimode SCSI 9 Line Terminator
FEATURES
•
Auto Selection Single Ended (SE) or
Low Voltage Differential (LVD)
Termination
•
Meets SCSI-1, SCSI-2, Ultra2 (SPI-2
LVD), Ultra3, Ultra160 (SPI-3) and
Ultra320 (SPI-4) Standards
•
2.7V to 5.25V Operation
•
Differential Failsafe Bias
•
Thermal packaging for low junction
temperature and better MTBF
•
Master/Slave Input
•
Supports Active Negation
•
3pF Channel Capacitance
DESCRIPTION
The UCC5630A Multimode SCSI Terminator provides a smooth transition
into the LVD SCSI Parallel Interface (SPI-2, SPI-3, SPI-4). It automatically
senses the bus, via DIFFB, and switches the termination to either single
ended (SE) or low voltage differential (LVD) SCSI, dependent on which
type of devices are connected to the bus. The UCC5630A can not be used
on a HVD, EIA485, differential SCSI bus. If the UCC5630A detects a HVD
SCSI device, it switches to a high impedance state.
The Multimode terminator contains all functions required to terminate and
auto detect and switch modes for SPI-2, SPI-3 and SPI-4 bus architectures.
Single Ended and Differential impedances and currents are trimmed for
maximum effectiveness. Fail Safe biasing is provided to insure signal integ-
rity. Device/Bus type detection circuitry is integrated into the terminator to
provide automatic switching of termination between single ended and LVD
SCSI and a high impedance for HVD SCSI. The multimode function pro-
vides all the performance analog functions necessary to implement SPI-2
termination in a single monolithic device.
The UCC5630A is offered in a 36 pin SSOP package, as well as a 48 pin
LQFP package for a temperature range of 0°C to 70°C.
BLOCK DIAGRAM
HIPD
35
LVD
34
SE
33
(NOISE LOAD)
HIPD
REF 1.3V
LVD
1.3V
20
DIFSENS
2.15V
DIFFB
21
0.6V
MSTR/SLV
19
SE
110
–15mA
≤
I
SOURCE
≤
–5mA
50µA
≤
I
SINK
≤
200µA
SE REF 2.7V
SOURCE/SINK REGULATOR
124
56mV
– +
56mV
+ –
MODE
ALL
SWITCHES
UP
DOWN
OPEN
OPEN
124
56mV
– +
56mV
+ –
52.5
31
L9+
52.5
32
L9–
110
SE GND SWITCH
52.5
4
L1+
52.5
5
L1–
LVD REF 1.25V
10µA
SE
LVD
HIPD
ENABLE
SWITCHES
DISCNCT 17
DISCNCT
TRMPWR
36
SE GND SWITCH
18
GND
8
9
10
26
27
28
1
REG
PATENTED CIRCUIT DESIGN
HS/GND
Note: Indicated pinout is for 36 pin SSOP package.
UDG-98192
SLUS322C - SEPTEMBER 1999 - REVISED MARCH 2002
TI [ TEXAS INSTRUMENTS ]
